It is known to use industrial robots for loading and unloading workpieces in a press line, such as those employed for manufacturing vehicle body parts.
From the applicant's previous EP2101962 it is also known to use two cooperating robots, each provided with a rigid arm connected to the robot wrists and to a workpiece to be handled, which acts as a mechanical link between the two robots. This document also foresees the provision of a connecting bar or cross member between the robots, in order to avoid losing the mechanical link when a workpiece is released.
It is now relatively common, especially in the high speed segment, to employ large press lines not only for manufacturing large parts, but also for stamping two or even more smaller parts at the same time, such as for example left and right vehicle door panels. Handling devices have therefore been developed to simultaneously load and unload two or more workpieces in a press line.
In some cases, two presses in the same line have different distances between the centres of the dies: in this case, it is necessary to change the distance between the two workpieces between two consecutive stations of the press line.
The present developments may assist with handling workpieces in a press line that allows reliable operation and good performance also in cases where the distance between the centres of the dies may change from one press to another.